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Fix GC stats.
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Use wall clock time for per-domain time calculation.
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kayceesrk committed Jul 27, 2024
1 parent 973928d commit 9da95ca
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1 change: 0 additions & 1 deletion CHANGES.md
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@@ -1,4 +1,3 @@

### 0.5.1

* Fix support on ARM64 platforms (Linux and MacOS) (#34, @tmcgilchrist)
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2 changes: 1 addition & 1 deletion dune-project
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@@ -1,7 +1,7 @@
(lang dune 3.2)

(name runtime_events_tools)
(version "0.5.0")
(version "0.5.1")
(generate_opam_files true)

(source
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76 changes: 38 additions & 38 deletions lib/olly_gc_stats/olly_gc_stats.ml
Original file line number Diff line number Diff line change
Expand Up @@ -2,51 +2,50 @@ module H = Hdr_histogram
module Ts = Runtime_events.Timestamp

type ts = { mutable start_time : float; mutable end_time : float }

let total_gc_time = ref 0
let wall_time = { start_time = 0.; end_time = 0. }
let total_cpu_time = ref 0.

let domain_elapsed_times = Array.make 128 (0.)
let domain_gc_times = Array.make 128 0

let lifecycle _domain_id _ts lifecycle_event _data =
let lifecycle domain_id _ts lifecycle_event _data =
match lifecycle_event with
| Runtime_events.EV_RING_START -> wall_time.start_time <- Unix.gettimeofday ()
| Runtime_events.EV_RING_START ->
let ts = Unix.gettimeofday () in
wall_time.start_time <- ts;
domain_elapsed_times.(domain_id) <- ts
| Runtime_events.EV_RING_STOP ->
wall_time.end_time <- Unix.gettimeofday ();
let times = Unix.times () in
total_cpu_time := times.tms_utime +. times.tms_cutime
let ts = Unix.gettimeofday () in
wall_time.end_time <- ts;
domain_elapsed_times.(domain_id) <- ts -. domain_elapsed_times.(domain_id)
| Runtime_events.EV_DOMAIN_SPAWN ->
domain_elapsed_times.(domain_id) <- Unix.gettimeofday ()
| Runtime_events.EV_DOMAIN_TERMINATE ->
domain_elapsed_times.(domain_id) <-
Unix.gettimeofday () -. domain_elapsed_times.(domain_id)
| _ -> ()

let print_percentiles json output hist =
let ms ns = ns /. 1000000. in
let ms ns = ns /. 1_000_000. in
let mean_latency = H.mean hist |> ms
and max_latency = float_of_int (H.max hist) |> ms in
let percentiles =
[|
25.0;
50.0;
60.0;
70.0;
75.0;
80.0;
85.0;
90.0;
95.0;
96.0;
97.0;
98.0;
99.0;
99.9;
99.99;
99.999;
99.9999;
100.0;
|]
[| 25.0; 50.0; 60.0; 70.0; 75.0; 80.0; 85.0; 90.0; 95.0; 96.0; 97.0;
98.0; 99.0; 99.9; 99.99; 99.999; 99.9999; 100.0; |]
in
let oc = match output with Some s -> open_out s | None -> stderr in
let to_sec x = float_of_int x /. 1000000000. in
let real_time = wall_time.end_time -. wall_time.start_time in
let gc_time = to_sec !total_gc_time in
let total_gc_time = to_sec @@ Array.fold_left ( + ) 0 domain_gc_times in

let total_cpu_time = ref 0. in
let ap = Array.combine domain_elapsed_times domain_gc_times in
Array.iteri (fun i (cpu_time, gc_time) ->
if gc_time > 0 && cpu_time = 0. then
Printf.fprintf stderr
"[Olly] Warning: Domain %d has GC time but no CPU time\n" i
else
total_cpu_time := !total_cpu_time +. cpu_time) ap;

if json then
let distribs =
List.init (Array.length percentiles) (fun i ->
Expand All @@ -66,15 +65,17 @@ let print_percentiles json output hist =
Printf.fprintf oc "Execution times:\n";
Printf.fprintf oc "Wall time (s):\t%.2f\n" real_time;
Printf.fprintf oc "CPU time (s):\t%.2f\n" !total_cpu_time;
Printf.fprintf oc "GC time (s):\t%.2f\n" gc_time;
Printf.fprintf oc "GC time (s):\t%.2f\n" total_gc_time;
Printf.fprintf oc "GC overhead (%% of CPU time):\t%.2f%%\n"
(gc_time /. !total_cpu_time *. 100.);
(total_gc_time /. !total_cpu_time *. 100.);
Printf.fprintf oc "\n";
Printf.fprintf oc "GC time per domain (s):\n";
Array.iteri
(fun i x ->
if x > 0 then Printf.fprintf oc "Domain%d: \t%.2f\n" i (to_sec x))
domain_gc_times;
Printf.fprintf oc "Per domain stats:\n";
Printf.fprintf oc "Domain\t Wall(s)\t GC(s)\t GC(%%)\n";
Array.iteri (fun i (c,g) ->
if c > 0. then
Printf.fprintf oc "%d\t %.2f\t %.2f\t %.2f\n" i c (to_sec g)
((to_sec g) *. 100. /. c))
(Array.combine domain_elapsed_times domain_gc_times);
Printf.fprintf oc "\n";
Printf.fprintf oc "GC latency profile:\n";
Printf.fprintf oc "#[Mean (ms):\t%.2f,\t Stddev (ms):\t%.2f]\n" mean_latency
Expand Down Expand Up @@ -113,7 +114,6 @@ let gc_stats json output exec_args =
Hashtbl.remove current_event ring_id;
let latency = Int64.to_int (Int64.sub (Ts.to_int64 ts) saved_ts) in
assert (H.record_value hist latency);
total_gc_time := !total_gc_time + latency;
domain_gc_times.(ring_id) <- domain_gc_times.(ring_id) + latency
| _ -> ()
in
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2 changes: 1 addition & 1 deletion runtime_events_tools.opam
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@@ -1,6 +1,6 @@
# This file is generated by dune, edit dune-project instead
opam-version: "2.0"
version: "0.5.0"
version: "0.5.1"
synopsis: "Tools for the runtime events tracing system in OCaml"
description: "Various tools for the runtime events tracing system in OCaml"
maintainer: ["Sadiq Jaffer" "KC Sivaramakrishnan" "Sudha Parimala"]
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2 changes: 1 addition & 1 deletion runtime_events_tools_bare.opam
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@@ -1,6 +1,6 @@
# This file is generated by dune, edit dune-project instead
opam-version: "2.0"
version: "0.5.0"
version: "0.5.1"
synopsis: "Tools for the runtime events tracing system in OCaml"
description:
"Various tools for the runtime events tracing system in OCaml: minimal dependencies"
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